Audio signal-responsive device



Jan. 30, 1962 F. L. wAY

AUDIO SIGNAL-RESPONSIVE DEVICE Filed March 7, 1960 @www w his ATTORNEYSspines-s trated. This actuator comprises a moving coil transducer 41 ofthe same general type utilized in conventional loud speakers having amagnet element d2, which may be either an electro-magnet or a permanentmagnet, a central pole piece 43 projecting axially from one end of themagnet and another U-shaped pole piece 44 extending from the oppositeend of the magnet and having poles d5, 46 on opposite sides of the polepiece d3. A coil member 47 slidably supported for relative axial motionon the pole piece 43 has two lead Wires 43 and 49 which are connected toreceive the audio signals passed by the corresponding lter 13, 14, or15, a diode rectifier element Si) being inserted in one of these leadWires. As a result, the coil member 47 is driven axially on the polemember 43 by a force proportional to the amplitude of the audio signal.To transmit axial motion of the coil member 47 a shaft 51 is supportedfrom the coil by a spider S2, the shaft S1 being connected to theactuator member 16a, 17a, or 18a' of FIG. l.

Another form of actuator shown in FIG. 3 utilizes a f structure similarto the usual type of meter movement wherein a coil member 53 isrotatably supported between the spaced ends of two adjacent pole pieces54 and 55 of a magnet 56. Two lead Wires 57 and 58, one including adiode rectifier element 59, supply the audio signal to the coil memberl53. Consequently, the coil is rotated by a force having a magnitudeproportional to the amplitude of the audio signal so that an arm 6@carrying a pivotally mounted shaft 61 transmits the coil motion to drivethe actuator member 16a, 17a, or 18a of FIG. l longitudinally inproportion to the input signal level.

In FIG. 4 a typical step-switched impedance for use in the system ofFIG. l is illustrated. This device comprises a series of resilientContact ingers 62-68 supported in closely spaced parallel relation andcarrying adjacent contact elements @which may be small silver blocks,for example. Preferably, one end of each of the fingers is embedded in asupport member 70 while the other end rests against the inclined side 71of a wedge block 72, the fingers in the series having progressivelygreater length so that they normally are held in spaced parallelrelation by the wedge block. An actuator element 74, which is connectedto a corresponding actuator member 16a, 17a, or 18a of FIG. l, restsagainst the outer side of the contact element 69 of the shortest linger65 so that the resilience of the linger provides a restoring force forthe element 74, the actuator member, and the moving coil of theactuating device. ln a typical case, the resilience of the iingers isselected to provide a total restoring force of about fifteen grams whenthe actuator element 74 has moved suiciently to close all the contactsand the spacing between the contact elements is arranged so that thetotal travel of the actuator is approximately one-eighth inch.

Connected between each adjacent pair of fingers 62-63 is an impedanceelementv which may be one of a group of resistors 75-79 or may comprisethe winding 37 of an actuating solenoid of the type described abovewhich, as shown in FIGS. 1 and 4, is joined to the fingers throughconductors Si) and 81 and the lead wires 38, 39, or dit. Accordingly,the individual impedance elements in the group are shunted outsuccessively as the actuator element 74 moves in response to signals orincreasing amplitude.

At one end of the series of elements 75-79 a lead Wire 82 is connectedto one of the power lines 28, shown in HG. l, while a conductor S3 atthe other end or" the series leads to the lamp Z5, 26, or 27, thusconnecting all the impedance elements in series with the lamp. Althoughonly seven resilient fingers form the step switch illustrated in FlG. 4and the impedance comprises but six separate elements, it will bereadily apparent that any number of impedance elements may be utilizedif the number of resilient fingers is correspondingly increased.

In order to provide an immediate response to switch actuation the totalseries impedance ofthe elements 75-79 and the actuating solenoid 37 isselected to maintain the corresponding lamp at an operating level justbelow that suflicient to cast a perceptible amount of light through itscolor filter onto the object 30 when power is applied and none of thecontacts 69 is closed. Moreover, the values of the various impedanceelements are selected in accordance with the characteristics of the lampto decrease the series impedance as the corresponding contacts areclosed by the amounts necessary to generate uniform changes in lightintensities at all operating levels. For a volt, 150 watt lamptransmitting light through a typical blue filter, the total seriesimpedance required is about 600 ohms and the individual impedanceelements in a twenty-element group should have values in `decreasingprogression from about 100 ohms for the first element shunted, 90 ohmsfor the next element shunted, and so on down to about 4 ohms for thelast element in the series. The precise impedance values required toprovide uniform steps for any specific light source can be readilydetermined from a graph of light intensity of the desired color plottedagainst irnpedance in series with the lamp. Also, inasmuch asconventional incandescent lamps produce a relatively high proportion of'green light and an even higher proportion of red light as compared withthe blue light, a 40 watt lamp may be used as the red light source and a75 watt lamp for the green light source where the blue light source is awatt lamp.

In operation, audio signals from the source 18 are divided into threeseparate channels according to frequency by the filters 13, 14, and 15.In each channel the amplitude-sensitive actuator 16, 17, or 18 moves itsactuating member 16a, 17a, or 18a in accordance with the amplitude levelof the signals within the corresponding frequency range and this motionis transmitted to the actuator element 74 (FIG. 4) of the correspondingstepswitched impedance device. Because the resilience of the fingerelements `6..-63 provides mechanical damping for the actuator unit, thesystem responds only to changes in amplitude level and not to each cycleof oscillation of the audio signals.

in response to actuator element motion the impedance elements 75-79 ofthe impedance device are shunted successively by the contacts 69 inaccordance with increases in the amplitude of the audio signal, therebydecreasing the total impedance in series with the lamp 2S, 26, or 27. Atthe same time, current passing to the lamp through the impedanceelements liows through the solenoid winding 37, actuating the arms ofthe animated object 30 of FIG. 1 for as long as the contacts on thefingers @i and 65 remain separated. When these contacts close as thesignal amplitude increases, the solenoid is de-energized, moving thearms to their inactive position, while the reverse motion takes placewhen the contacts open on decreasing signal amplitude. In this way, thesystem provides an accurate and complete visible representation of thequality and intensity of variations in audio signal levels.

Although the invention has been described herein with reference tospecific embodiments, many modifications and variations therein willoccur readily to those skilled in the art. Accordingly, such variationsand modications are included within the intended scope of the inventionas defined by the following claims.

I claim:

l. A device for producing high fidelity visual representations of audiosignals comprising electric light source means, circuit means forconnecting the light source means to an electrical energy source,impedance means connected in series with the light source means having avalue selected to maintain the light source means at a thresholdoperating condition, mechanical switch means for reducing the impedanceof the impedance means in selected steps to provide substantiallyuniform changes in light intensity, and electromechanical actuator meanscom` prising fixed magnet means, coil means supported for oscillatorymotion in the magnetic field of the fixed magnet means connected to anaudio signal input, and linking means mechanically linking the coilmeans to the switch means, to activate the switch means in accordancewith changes in audio signal amplitude.

2. A device for producing yhigh fidelity visual represen tations ofaudio signals comprising a plurality of electric light source means,color filter means for each light source means transmitting light raysof a selected color, circuit means for connecting each light sourcemeans to an electrical energy source, impedance means connected inseries with each light source means having a value selected to maintainthe light source means at a threshold operating condition, mechanicalswitch means for each impedance means for reducing the impedance inselected steps to provide substantially uniform changes in lightintensity, electromechanical actuator means for each switch meanscomprising fixed magnet means, coil means supported for oscillatorymotion in the magnetic field of the fixed magnet means connected to anaudio signal input, and linking means mechanically linking the coilmeans to the switch means, to actuate the switch means in accordancewith changes in audio signal amplitude, and a plurality of electricalfilter means each connected to one of the actuator means and adapted totransmit a selected audio frequency range thereto from an audio signalsource.

3. A device for producing high fidelity visual representations of audiosignals comprising electric light source means, circuit means forconnecting the light source means to an electrical energy source,impedance means connected in series with the light source means having avalue selected to maintain the light Source means at a thresholdoperating condition, mechanical switch means comprising a plurality ofspaced resilient conducting members electrically connected to selectedpoints in the impedance means to shunt the impedance means inpredetermined steps when adjacent conducting members are joined, thepoints being selected in accordance with the operating characteristicsof the light source means to provide substantially uniform changes inlight intensity as the resilient elements are joined successively, andelectromechanical actuator means comprising fixed magnet means, coilmeans supported for oscillatory motion in the magnetic field of thefixed magnet means connected to an audio signal input, and linking meansmechanically linking the coil means to the switch means, to actuate theswitch means in accordance with changes in audio signal amplitude.

4. A device according to claim 3 wherein the linking means comprisesshaft means longitudinally movable in response to coil motion todisplace the resilient conducting members laterally and urge adjacentmembers successively into contact.

5. A device according to claim l wherein the magnet means includes alongitudinal pole piece and the coil means is movable longitudinally onthe pole piece.

6. A device according to claim l wherein the magnet means includes apair of opposed pole pieces and the coil means is rotatably supportedbetween the pole pieces and carries an arm pivotally linked to thelinking means.

7. A device according to claim 3 including an object y having a movableme-mber actuatable by electromechanical drive means, andelectromechanical means for operating the movable member having aselected electrical impedance connected to form a portion of theimpedance means.

8. A device according to claim 7 wherein the object is positioned to beilluminated by the light source means.

9. A device for producing high fidelity visual representations of audiosignals comprising a plurality of electric light source means, colorfilter means for each light source means transmitting light rays of aselected color, circuit means for connecting each light source means toan electrical energy source, a plurality of electrical impedanceelements of progressively decreasing value connected in series with eachlight source means and having a total impedance selected to maintain thelight source means at a threshold operating condition, mechanical switchmeans for each plurality of impedance elements comprising a plurality ofspaced resilient conducting members electrically connected to thejunctions between adjacent impedance elements in the series to shunt theelements in sequence when adjacent conducting members are joined,

electromechanical actuator means for each switch means comprising fixedmagnet means, coil means supported for oscillatory motionkin themagnetic field of the fixed magnet means connected to an audio signalinput, and linking means mechanically linking the coil means to theswitch means, to join the resilient fingers successively to shunt thecorresponding impedance elements, starting with the element having thehighest value, and a plurality of electrical filter means eachtransmitting selected portions of the audio frequency range to one ofthe actuator means.

10. A device according to claim 9 including an object having a movablemember, and solenoid means for actuating the movable member having awinding constituting one of the impedance elements in one of thepluralities of impedance elements.

References Cited in the file of this rpatent rUNITED STATES PATENTS1,714,504 Greenwalt May 28, 1929 1,977,997 Patterson Oct. 23, 19342,246,301 Hanna et al. June 17, 1941 2,275,283 Burchfield Mar. 3, 19422,717,351 Christian et al. Sept. 6,y 1955

